Sound translating apparatus



F 16, 1943. .14. J. HASBRQUCK, JR 2,311 385 I SOUND TRANSLAT'ING APPARATUS Filed May 1, 1940 j ways connected in means of a reversing STATS 2,3113% SOUND rasnsm'rme In, Me'rchantviile, N. J., as-

Radio Corporation of America, a cor-- poration of Delaware Harold J. Hasbrouck,

signor to snares Application May 1, 1940, Serial No. 332,635

13 Claims. (Ci. ire-man) This invention relates to sound translating apparatus, and more particularly to a sound translating device which may be employed for either hill-and-dale operation or for lateral cut operation, the principal object of my present invention being to provide a sound translating device of this type which is simple in construction and highly efficient in use.

More particularly, it is an object of my present invention to provide an improved combination lateral cut and hill-and-dale sound translating device in which the type of operation is selected by a means external to the piclrup itself.

Another object of my present invention is to provide an improved sound translating device as aforesaid which will provide .high quality reproduction from either lateral cut records or from records of the hili-and-dale type.

Still another object of my present invention is to provide an improved sound translating device as aforesaid which employs very low needle pressure and which, therefore, will insure increased switch being determined by the type of service or operation which the device is called upon to perform.

The entire struc ure is of very light mass and has great flexibility, its vertical compliance beinl relatively high. of any moving iron, distortion is extremely low The device also has a low mechanical impedance The weight on the record is of the order of approximately one ounce. Thus, wear on the records, and particularly records having surface coatings of soft material, is greatly reduced.

One of the requirements in a combinatior translating device of this type is that it shall in insensitive to vertical modulation when playim a lateral cut record. Due lateral out records, the result of cutting with r cutting stylus having a plane or flat advancn cutting face and thereafter reproducing with a stylus having a spherical tip, a vertical componentresults at twice the signal frequency, an

life of records, particularly records having surface coatings of relatively soft material. A further object of my present invention is to provide an improved sound translating device of the type set forth which will have a long life.

It is also an object of my present invention to provide an improved sound-translating device as aforesaid which is much less subject to damage than similar devices heretofore known.

According to this invention, [provide a pair of serially connected, straight conductors in separate air gaps and form the conductors with a center hinge which flexes about an axis normal this seriously affects the quality of reproduction This double frequency cancels out in my im proved translating device becauseof the two out of-phase conductors which have a common cen ter'tap. The best analogue is a push-pull ampii fier wherein second harmonic distortion is car. celled in the output transformer.

In connection with my improved translatir device, I preferably employ a diamond point nu die and mount it in a manner such that, in spl' of the apparent delicate construction of the d:

to the conductors when the device operates on hill-and-dale records and which undergoes torsion about an axis parallel to said conductors when the device operates on a lateral cut record.

The voltages generated by said conductors, as they move in their respective air gaps either simultaneously in the same direction when operating upon a record taneously in opposite directions when workingon a record of the lateral cut type, are brought out to a suitable ampliflerby means of a pair of small transformers the primary windings, of which are serially connected and the common point of which is connected'to the aforemen -tioned hinge which constitutes a center tap for The secondary windings ofthe I the conductors. transformer may be in parallel relation,

connected-either in series or but in any case they are alcurrent aiding relation by switch, the position of; the

of hill-and-dale type or simulvice, it is less easily damaged than similar tran: lating devices heretofore known because of 1 vertical flexibility, which enables the needle 1 withdraw if it is dropped on or slid-lateral across a record. The life of the diamond poi: of my improved translating device on shells abrasive discs, such as are commonly used home entertainment, is in excess of 5000 play ings, while on non-abrasive recordsa life from two to three times as much is not improi able. The needles are so mounted that they on very easily be replaced whenworn.

The novel features that I consider characterh tic -of my invention are set forth with partici larity in the appended claims. The invention i self, however, both as. to its organizational. method of operation, as well as additional oi jects and advantages thereof, will best be undo: stood from the following' description of one on bodiment thereof, when read in connection wit the accompanying drawing, in which Figure 1 is a sectional view of one form l Because of this and the absence I to thepinch effect ir Figure 3 is a perspective view of the'movabie conductors, and

Figure 4 is a circuit diagram showing the man- I ner in which the conductors may be connected to an, amplifier. 1 1 Referring more particularly to the .drawing, wherein similar referencecharacters designate corresponidng parts throughout, there is shown a-supporting arm I having a'base 3 to which are-fixed three pole pieces 5, 1 and 9, the pole pieces being spaced from each other to provide two parallel air gaps -l I and. i3. Resting upon the end pole pieces 5 and 9 is a magnet i5 which supplies the flux for the air gaps H and 13. The magnet I 5 may be held in place by means of a spring clamp H, in turn held in place by a cover It which is secured to the supporting arm I, as by means of one or more screws 2!.

Secured to the base 3 by means of a flexible member, such as a wire 23, which is flexible vertically and laterally but not longitudinally'is a conductor 25 formed preferably out of a single piece of some suitable, fiat, resilient material, such as beryllium, copper or Duralumin. The conductor 25 is bent into a substantially U shape to provide a pair of parallel arms 21 and 29 ex tending from the base of the U, or cross arm 3!, the arms 21 and 29 extending in parallel rela tion through the air gaps ll and i3, respectively, and terminating in ofiset portions 210: and. Eta by means or which the arms 21 and 29 are respectively clamped between insulating strips 32 to the inner ends of the pole pieces 5 and 8,-as by screws 33 and a clamping plate 35. The end portions 21a. and 29a. of the arms 21 and 29 are provided, respectively, with upwardly extending and rearwardly bent tabs 21b and 29b to which may be secured suitable conductors for external connection to the primary winding of one or more transformers, as will be hereinafter described in greater, detail. The conductor 25 is also pro vided with a-tongue131 which is bentback from the-cross arm '3l and extends in substantially parallel relation to the parallel arms 21 and 28, but in a plane substantially normal to the planes of-the ribbon conductors 21 and 29 and to the plane of the cross arm 3|. The tongue 31 is secured to the center pole piece 1 by a screw 39 and is provided with an upwardly turned tab 31a to which a suitable lead may be secured for external; connection.

It will be obvious, from the foregoing description, that the conducting elements or arms 21,

and 29 are free to move in their respective air gaps simultaneously either in the same direction or in opposite directions. The" cross arm 3! is provided with a groove 3 la in which may be suitably received a needle 4| having a diamond or any other suitable point adapted either to record a sound'groove in a blank disc or to track and reproduce from the groove of a recorded record.

When the needle 4i operates in a record of the hill-and-dale type, the arms 21 and 29 move in phase simultaneously in the same direction in their respective air gaps withthe tongue 31 flexing about an axis substantially normal to the planes of the parallel arms 21 and 29 and the cross arm moving substantially linearly in itsown plane. On the other hand, when the needle 4| operates in a groove of the lateral cut type, the arms 21 top plan view thereof with the .cover and magnet removed,

air gaps, that is, when one arm moves down in its air gap, the other arm moves up in its air gap, and vice versa. In this case, the tongue 31 undergoes torsion about an axis which extends through the center of the screw 39, or along the center of the tongue 31, and parallel to the arms 21 and 28, as the cross arm rotates in its own plane and about the torsion axis of the -tongue 31 in responseto actuation of the 1188':

.stantially the whole length of the cross arm 3i.

However, two small blocks thereon, one placed on either side of thegroove em, may also serve satisfactorily. The block 43 is found to be particularly effective when the device is operating with hill-and-dale records at around 6000 cycles, but the block or blocks E5,- as the case may be, will be found to be efiective when the device is used with either hill-and-dale or lateral cut records in the region of 9000 cycles.

Because of the low electrical impedance of the conducting elements 21 and 23, it is impractical to bring out leads directly from these elements. Consequently, I prefer to employ two small transformers 1 and 49 the primary windings 41aand 49a of which, respectively, are serially connected at a common point 5 l.- lhe tongue 31 acts as a center tap for the conducting elements 21 and 29 and may be connected to the common point by a lead 53, a lead 55 connecting the conducting element 21 to the free end of the winding 41a and a lead 51 connecting the conducting element 29 to the free end of the winding 49a. The secondary windings 41b and 4912, respectively, of the transformers 41 and 49 may also be connected in series, with each other by means of a reversing switch 59, and the output and 29 move 180 out of phase in their respective from the transformers 41 and 49 may be fed to a suitable amplifier through the leads BI and 83. When the device is operated on a hill-and-dale record and the conductors 21 and 29 move in unison in the same direction, the current in the secondary windings 41b and 4% also flows in one direction and the. switch 59 may be thrown to the position A (Fig. 4) to connect the secondary windings 41b and 49b in series, with the currents in the two windings in aiding relation. "When, however, the device is operating on a lateral cut record, the arms or conductors Z1 and 29 move simultaneously in opposite directions, whereupon .the current in the secondary winding 41b flows in an oppositedirection from that in which the current in the winding 4% flows.

it is necessary to reverse the polarity of the Consequently,

winding 41b with respect to the winding 49!), and for this purpose, the reversing switch 59 is .thrown to the B position (Fig. 4). The secondary windings are therefore again connected in series, and the currents in the two secondary windings are again in aiding relation, just as in the case where the device operates with a hilland-dale' record.

Although I have shown and described but one embodiment of my invention, I am fully aware that many other modifications thereof are possiole. For example, if desired, the parallel conductors or arms 21 and as may each be provided with one or more transverse corrugations or grooves to' stiffen them somewhat. Other changes of a similar nature will, no doubt, also suggest themselves to those skilled in the art. I, therefore, desire that my invention shall not be limited except insofar as is made necessary by the prior art and by. the spirit of the appended claims.

I claim as my invention:

1. In an electrical signal the combination of means providing a magnetic circuit and including two air gaps, and a subetantially U-shaped conductor having its parallel arms disposed one in each of said air gaps, the ends of said arms being anchored to said translating device, I

cross arm is movable linearlyto cause said parallel arms to move simultaneously in the samedirection in their respective air is movable parallel arms to move si- 6. In an electrical signal translating device adapted to reproduce, sound from records of either the hill-and-dale type or the lateral cut type, the combination of means providing a magmeans and the cross arm of said conductor being ireely supportediror movement in its own plane either substantially linearly or rotatably, and hinge means coupled to said cross arm, said hinge means including two hinge axes about one of which said cross arm is movable-linearly to cause said paralle1 arms to move simultaneously in the same direction in their respective air gaps andabout the other of which said cross arm is movable rotatably to cause said parallel arms to move simultaneously in opposite directions in their respective air gaps.

2. In an electrical signal translating device, the combination of means providing a magnetic circuit and including two air gaps, and a sub-- stantially- U-shaped conductor of resilient material having its parallel arms disposed one in each or said air gaps, said conductor also having a tongue thereon extending from the cross arm of the U and in substantially parallel relation to said parallel arms, the ends of said parallel arms and a portion of said tongue being anchored to said means, and said cross arm being freely supported for movement in its own plane, said conductor and said-tongue being formed oi a single integral piece of flat material, and said tongue and parallel arms all being formed by bending said parallel arms and said tongue out of the plane of said cross arm.

' 3. The invention set forth in claim 2 characterized in that said tongue is disposed in a plane substantially normal to the 'plane of said parallel arms.

e. The invention set" forth in claim 2 characterized in that. said tongue is disposed in a plane substantially normal to the planes of said parallel arms and also to the plane of said cross arm, saidparallel arms being adapted to move simultaneously in their respective air gaps either in the same direction 01 in opposite directions, and said tongue'being adapted to act as a hinge for said parallel arms to flex about an axis normal to said parallel arms when said parallel arms move simultaneously in the same direction and to flex torsionally about an axis parallel to said parallel arms when said parallel arms move siarm, said hinge means in-' eluding two hinge axes plane, said parallel arms thereby being adaptedto' move simultaneously in their respective air gaps either in the same direction or in opposite tfirecq tions, said tongue being adapted to act as a e netic circuit and including two air gaps, a substantially U-shaped conductor of resilient material havingits parallel arms disposed one in each oi? said air gaps, said conductor also having a tongue formed integrally therewith and extending from-the cross arm of the U in substantially parallel relation to said parallel arms,

the ends of said parallel arms and the end of said tongue being anchored to said means whereby said cross arm is freely supported for inove merit in its own plane, and a needle carriedby said cross arm adapted to cooperate with a phonograph record groo e, said tongue serving as a hinge for said conductor and flexing about an axis normal to said parallel arms when said needle is actuated by, a hill-and-dale record whereby said parallel arms move simultaneously in the same direction in their respective air gaps, and said tongue flexing torsionally about an axis parallel to said parallel arms when said needle is actuated by a lateral cut record whereby said parallel arms move simultaneously in opposite directions in their respective air gaps.

- '7. The invention set iorth'in claim 6 characterized by the addition of a damping member on said cross arm.

8. The invention set. forth in claim 6 char-' act-erized by the addition of a damping member on said tongue.

9. The invention set forth in claim 6 char acterized. by the addition of a damping member on said cross'arm, and characterized further by the addition of a second damping member on,

in substantially'parallel relation to said parallel arms, said tongue lying in a plane substantially normal to the planes of said parallel arms and also to the plane of said cross arm, the ends of said parallel arms and a portion of said tongue being anchored tosaid means whereby said Cli-es arm is supported for free movement in its own for said paralle1 arms to flex about an axis normal to said parallel arms when said parallel arms move simultaneously inthe same direction and to-flex torsionally about an axis parallel to said parallel arms when'said parallel arms move simultaneously in opposite directions, at east one damping member secured to said cross rm, and

gaps and about the other of which said cross arm 'rotatably to cause said multaneously in opposite directions in their reat least one other damping member secured to said tongue.

11. The invention setforth in claim 10 characterized in that one of said damping members is particularly effective over a. predetermined range when said parallel arms move in the same direction, and characterized further in that the other of said damping members is particularly efiective over another range at least when said parallel arms move in opposite directions.

. 12. In an electric signal translating device, the combination of means providing a magnetic held and including two air gaps, a pair of linear conductors disposed one in each of said air gaps, meansanchoring one end of each of said conductors against movement, the other ends of said conductors being connected to each other and being freely supported for vibratory movement, a resilient hinge member extending from the junction of said conductors, and means anchoring said hinge member to provide two hinge axes for said conductors about'one of which said conductors are free to move in phase with each other in their respective air gaps andabout the other of which said conductors are free to move 180 out of phase with each other in their respective air gaps.

13. In an electric signal translating device, the

combination of means providing amagnetic cirsuit and including two air gaps, a panot linear conductors disposed one in each of said air gaps;

means anchoring one end of each of saidconductorsagainst movement, the other 'ends of said conductors being freely-supported ior vibratory movement, means connecting the free ends of said conductors and movable therewith, a resilient hinge member connected to said last named means and extending substantially par- 

